Energy Code - Overview

What Is It?

Our Seattle Energy Code regulates the energy-use features of new and remodeled buildings, including:

  • Building Envelope: requirements for roofs, walls, window,s etc. to control heat loss and air leakage 
  • Heating, Ventilation and Air Conditioning (HVAC): efficiency for heating and cooling equipment
  • Water Heating: equipment efficiency and controls
  • Lighting: number and type of lighting fixtures and controls
  • Metering, plug load controls, transformers, motors, and renewable energy

Energy Code Amendment

The City Council recently passed an amendment to the 2018 Seattle Energy Code that extends the requirement for heat pump water heaters to non-residential commercial buildings. This amendment will take effect for permit applications submitted as of April 1, 2022.

For new construction, the changes to Section C404.2.3 clarify that the new requirements apply to commercial buildings with more than 15 kW of water heating capacity. The additional efficiency credits table (Table C406.1) is also modified to eliminate credit for option 8, and to reduce credit for option 9, since heat pump water heating will now be required in the base code. For existing buildings, the water heating requirements in Section C503.5 apply to substantial alterations projects and to projects in which a building's central water heating system is augmented or replaced. "Central" water heating systems are systems that serve multiple areas of a building, not individual water heaters that serve a single use.

The amendments include some important exemptions. The most significant exception is number 8, which allows a gas or electric resistance water heating system to be replaced in kind in an existing commercial building. Other exceptions include: an electric resistance water heater in a tenant space up to 15 kW capacity, a unitary heat pump water heater in a conditioned space, and systems in commercial buildings served by district steam systems. Note: These exceptions do not apply to hotel or multifamily buildings.

For further information, contact SDCI's energy code advisor Duane Jonlin, duane.jonlin@seattle.gov.

Read the Code

Read 2018 Energy Code Amendment Heat Pump Scope Change for the consolidated approved code change language.

Below is a read-only version of the 2018 Seattle Energy Code with errata. You can buy a full pdf version from iccsafe.org. Print copies are available for sale through the Seattle Services Portal. See our pricelist and our ordering instructions.

The 2018 Seattle Energy Code contains substantial copyrighted material from the 2018 International Energy Conservation Code which is proprietary to and copyrighted by International Code Council, Inc. The licensed material is copyrighted by the International Code Council, Inc., has been obtained and reproduced with permission. The acronym “ICC” and the ICC logo are trademarks and service marks of ICC. ALL RIGHTS RESERVED.

Seattle Energy Code - Commercial


Seattle Energy Code - Residential

Washington State Appendices

Below is a read-only version of the 2015 Seattle Energy Code. You can buy a full version from iccsafe.org.

The 2015 Seattle Energy Code contains substantial copyrighted material from the 2015 International Energy Conservation Code which is proprietary to and copyrighted by International Code Council, Inc. The licensed material is copyrighted by the International Code Council, Inc., has been obtained and reproduced with permission. The acronym “ICC” and the ICC logo are trademarks and service marks of ICC. ALL RIGHTS RESERVED.

Seattle Energy Code - Commercial


Seattle Energy Code - Residential


Washington State Appendices

Residential or Commercial Energy Code?

The Seattle Energy Code chapters that apply to your project depend on whether your project is a "residential building" or a "commercial building" as defined in the energy code. See below for a breakout of the chapters by each version of the code.

  • Use the “residential buildings” provisions for single-family homes, duplexes, and townhouses
  • Use the “residential buildings” provisions for 1-, 2-, and 3-story multifamily buildings
  • Use the “commercial buildings” provisions for 4-story and higher multifamily buildings
  • Use the “commercial buildings” provisions for non-residential buildings

Addition, Alteration, & Repair Projects

2015 and 2018 Code

  • Use Chapter 5 in the “residential building” portion of the code for single-family homes, duplexes, and townhouses, and for 1-, 2- and 3-story multifamily buildings
  • Use Chapter 5 in the “commercial building” portion of the code for non-residential and for 4-story and higher multifamily buildings

Proposed Changes

In March, the Seattle City Council hosted a public meeting about the proposed 2018 Seattle Energy Code amendment requiring heat pump water heating (HPWH) in commercial buildings

Public Comments

Background Documents